Abstract: To reduce the heat present in hot hydraulic oil, the oil is passed through a heat exchanger in heat exchange relation with water. The temperature of the water entering the exchanger is at least 28.degree. C. and the quantity of water circulated through the exchanger is such that the difference between the ingoing and outgoing temperatures of the oil at the heat exchanger is not more than 10.degree. C.

Abstract: An injection molding machine having a system for detecting nozzle leaks including a thermocouple positioned in the tunnel opening of a stationary platen of the machine at a predetermined location relative to the nozzle to sense instantaneous temperature at the location. A controller coupled to the thermocouple receives signals from the thermocouple and activates an alarm when the temperature in the tunnel opening falls outside of a predetermined normal operating temperature range.

Abstract: A die spool for the extrusion of thermoplastic materials includes an axially split elongate spool body so as to be separable into first and second spool segments. The spool segments collectively establish the spool body and also define an axially oriented extrusion cavity through which thermoplastic material is conveyed. An alignment system ensures that only a single orientation of the extrusion axis is possible when the die spool is coupled to another similar die spool (or to an extrusion die associated with an extruder). A die spool assembly may therefore be provided which is comprised of a number of individual die spools. Preferably, a decreasing temperature gradient is established within the extrusion cavity of the die spool assembly (as may be accomplished by controllably operating electrical resistive heater elements) so as to at least partially solidify the thermoplastic extrudate therewithin.

Abstract: Control apparatus for an injection molding machine having a sensor provided for the injection molding machine for producing a signal representing the quality of the molded product or a molding condition of the injection molding machine, a set value memory device in which a permissible range of the signal is set, a judging member for judging as to whether the signal lies in the permissible range, a production lot data memory device containing control data for the injection molding machine with respect to a lot now being produced, and a destination table showing a destination of the data corresponding to a result of judgment of the judging member, a controller for controlling the injection molding machine in accordance with the control data stored in the production lot memory device, and another memory device for storing a plurality of sets of the production lot data regarding various lots or production conditions, and a storing device for determining a destination of the production lot data based on the result

Abstract: Method for improved melt quality of thermoplastics processed in reciprocating-screw molding, especially optical injection molding processes. In a reciprocating-screw injection-drive unit (4) is a barrel (53) and screw (15). Screw (15) is double flighted throughout its melting or transition zone (2), to form melt channel (48) and solids channel (50) separated by melt-filtering flight element (47), and kept in fluid communication by melt-transfer apertures (47 or 55 or 56) or substantially nonvertical ramped barrier flight geometry (not shown). The largest energy input for melting is directly provided by thermal conductivity, via electrical resistance heating elements.

Abstract: A running web of thermoplastic material is uniformly relaxed across its width by monitoring the tension in its marginal sections and by adjusting the corresponding heaters adjacent the path of the marginal sections. The median section of the web is relaxed in response to generation of a signal which denotes the tension profile across the entire web and is obtained as a result of the processing of signals which denote the monitored tension in marginal sections of the web. Those sections of the web wherein the tension is higher are heated less intensively than the sections wherein the tension is lower.

Abstract: A process for tempering tools, for use on the form tools of extrusion forming machines. In the injection molding tools there are conduction circuits for a coolant which are connected to ducts for the inflow and backflow of the coolant. Valves (4) control the throughflow of the coolant. There are temperature sensors (5, 6) in the ducts for the inflow and backflow of the coolant. The temperature sensors (5, 6) are connected to a computer (7) which controls the opening and closing times of the valves (4) as a function of a nominal difference fed in between the inflow and backflow temperatures of the coolant. Advantageously, a temperature sensor (3) which is also connected to the computer (7) is provided on the form tool.

Abstract: An apparatus for liquefying a thermoplastic, high-polymer material has a supply container for the thermoplastic material, heating means for heating the material in the supply container, a base part disposed beneath the supply container and containing a collecting trough for the liquefied thermoplastic material and control means regulating the heating means in dependence upon a comparison between a predetermined desired value and an actual value detected by a sensor. In order to be able to follow even rapid changes of the operating conditions the amount of liquefied thermoplastic material conveyed out of the collecting trough is detected as actual value and supplied to the control means; a suitable measure of this amount is in particular the speed of rotation of a pump serving as conveying means to convey the liquefied material from the collecting trough.

Abstract: A method and an apparatus for measuring and controlling foam sheet blow-up in a thermoformer oven. Control of the oven operation is achieved through monitoring the measured blow-up of a material in the thermoformer oven at a sensing location in a forming station receiving the material from the over in order to regulate the thickness of the plastic material prior to its conveyance into said forming station. This is effected by varying the rate of advance and dwelling time of the material in the oven, and optionally, also concurrently regulating the temperature in the oven to optimize control over material blow-up.

Abstract: The heat-sink capacity of a well-insulated dome curing press lends itself to saving external steam (flowed over the exterior of a mold in the press) when curing an article. Despite shutting off the external steam at about the half-way point in the normal heating cycle, or sooner, the temperature swing at a point 2 inches within the mold is less than 10.degree. F. This small swings allows the point of least cure (PLC) to receive the required number of cure equivalents long after the external steam supply is shut off, that is, while the press is "coasting". In the mean while, the internal heating and cooling cycle of the press may also be shortened for maximum energy savings, or left unchanged. Though the external steam is shut off before the PLC has received the required or specified number of cure equivalents at the PLC, the press-open to press-close cycle remains the same, and the quality of the cure is not measurably affected.

Abstract: A trapped rubber molding method including a die positioned within a fixed-volume, rigid mold, the die being surrounded by an integral solid silicone rubber material which has been cured within the mold at an elevated temperature. The die and mold closure are thermally isolated from the remainder of the mold. The die and the silicone rubber material adjacent thereto are selectively heated and cooled. The opposite end of the mold is selectively heated and cooled. This configuration results in the ability to independently control temperature and pressure on the molded part during the molding process.

Abstract: An automatic control for an extruder has a temperature sensor which monitors the exit temperature of the extrudate and several pressure transducers which monitor the pressure within the extruder to control the cooking of the mash inside the extruder to ensure production of high quality extrudate. The controller monitors and controls the temperature and moisture content of the mash in the extruder by controlling the input of various ingredients and also the cooling or heating of the mash near the exit of the extruder through a heat exchanger.

Abstract: A method for monitoring and controlling the wall thickness of an extruded profile of heated polymeric material that issues from an extrusion die. The die includes a plurality of discrete sectors each having a controllable heat source and a temperature sensor, and the temperature at each particular sector is controlled and adjusted in order to change the measured wall thickness corresponding with that particular sector as necessary to provide a desired wall thickness distribution. A characteristic curve for the particular material is provided as an input quantity and involves the relationship between a change in extrusion temperature versus the corresponding change in wall thickness, and that relationship is utilized to effect rapid adjustment of wall thickness by means of a temperature change in order to provide a finished article having the desired thickness profile and without having excessive material, to thereby reduce the weight and cost of the extruded article.

Abstract: A method and an apparatus for measuring and controlling foam sheet blow-up in a thermoformer oven. Control of the oven operation is achieved through monitoring the measured blow-up of a material in the thermoformer oven at a sensing location in a forming station receiving said material from said oven in order to regulate the thickness of the plastic material prior to its conveyance into said forming station.

Abstract: In preparing a film by extruding a molten thermoplastic resin, a heater in which a temperature profile varying in the width direction can be set is arranged in the width direction in the vicinity of a die lip, and a temperature sensor for detecting a resin temperature profile in the vicinity of the outlet of the die lip and a sensor capable of detecting a thickness profile of a film or the like in the width direction are disposed. The output of the heater is controlled according to signals from the temperature sensor and thickness sensor to automatically adjust the thickness of the film or the like in the width direction, whereby a homogeneous film with a reduced thickness unevenness can be stably prepared with a high precession of control of the thickness unevenness. .

Abstract: A method for manufacturing molded products of polyethylene terephthalate by injection molding or extrusion molding a material containing polyethylene terephthalate as the principal component characterized by using virgin and/or waste polyethylene terephthalate of average molecular weight of more than 10000 to which polymer such as nylon and/or inorganic fillers can be added as required, and molding said material under the following molding conditions by a general type or vent type molding machine:(a) Control of a temperature of a cylinder of the molding machine in the range of melting temperature of resin plus/minus 35.degree. C., and(b) Control of the staying hour of resin in the cylinder to be within 15 minutes.

Abstract: A melter for adhesives such as hot melt adhesives or the like including a high melt zone having high melt heater means for heating the adhesive in the high melt zone to a preselected application temperature, a feed hopper positioned vertically above the high melt zone and a cooling mechanism positioned vertically above the high melt heater means to create a thermal barrier between the high melt heater means and the feed hopper to prevent migration of heat from the high melt zone to the feed hopper. The present invention also relates to a method for preparing adhesives for application including heating the adhesive to a preselected application temperature in a high melt zone and forming a thermal barrier in an area vertically above the high melt zone to limit the upward migration of heat from such zone.

Abstract: The invention relates to producing relatively flaw free zirconia ceramic shapes requiring little or no matching by superplastic forging of a fully sintered or partially sintered preform. The preform is prepared by providing a starting powder comprising by weight from about 70% to about 100% zirconia and from about 0 to about 30% of stabilizing additives, e.g. commerically available TZ-3Y powder, cold pressing to obtain a preform of green density ranging from about 30% of theoretical density to about 75% of theoretical density and partially or fully sintering at atmospheric pressure, e.g. in argon or air at a temperature ranging from about 900.degree. C. to about 1900.degree. C. The superplastic forging is carried out by isothermally pressing the partially or fully sintered preform into substantially final shape utilizing a temperature and strain rate such that surface cracks do not occur, e.g. utilizing a temperature of 1310.degree. C.

Abstract: A method of molding oriented structural yarn/polymer matrix composite structural articles in which a preform of oriented yarn layers saturated with a resin is placed in a shape-defining mold, which is put in an enclosure, and subjected to heat and pressure to cure the resin, after which a cooling medium may be introduced. To enable the use of lightweight multi-part molds, and a mixture of pressure is distributed evenly, an internal liner is collapsed about the mold prior to curing. The process is extremely productive, and allows for accuracy and reproducibility through the use of real time temperature monitoring and closed loop feedback control.

Abstract: An arrangement for controlling the process temperature in an industrial process involving an extruding operation includes a summing element which sums the difference between the process temperature and a setpoint temperature with the rate of change of the process temperature and conveys this sum to a proportional and integral controller so that the output thereof acts in an inverse manner with the process temperature. This output of the controller is summed with the change of temperature rate which has been fed forward, to generate a demand signal. The demand signal is shaped and compared to a ramp waveform to generate a variable frequencey pulse for controlling a heating and/or cooling device associated with the extruding device. A change of speed rate can also be summed to form the demand signal.

Abstract: An extrusion die-set is disclosed for extruding plastic film, in which the nozzle-lips (6,8) are heated, for the purpose of allowing production speed to be raised without losing film-quality. The heaters include aluminum rings (62,82) embedded in grooves in the dies near the nozzle lips. The surfaces (66,67,86,87) of the ring that face away from the nozzle lips are cut away, so that heat transfer to the bulk of the dies (60,80) is reduced. The disclosed heaters eliminate the problem of hot-spots and cold-spots around the circumference of the nozzle. The nozzle lips can run several degrees hotter than the bulk of the dies, using the disclosed heaters.

Abstract: The preformed assembly of a transparent sheet material and a gasket adhered to the periphery thereof, and the method for producing the assembly. Preferably, the sheet material is glass and the gasket is formed of a thermosetting polyurethane material. The material, curable to produce the gasket, is injected into a mold cavity and thence by controlling the attendant parameters, the autogeneous pressure incident to polymerization causes the material to be urged into intimate contact with mold cavity and the sheet material. After the material has been cured sufficiently, the resultant assembly is removed from the mold cavity.

Abstract: An apparatus for cooling a tubular polymer film material which is being extruded, and more particularly, an apparatus for extruding tubular thermoplastic films including two tandem spaced air rings for controlling the cooling rate and production speeds of the thermoplastic films during extrusion thereof. Moreover, there is also disclosed a method for the cooling of an extruded tubular thermoplastic film material through the utilization of a tandem air ring cooling structure.

Abstract: A method and an apparatus for controlling foam sheet blow-up in a thermoformer oven. Control of the oven operation is achieved through monitoring the measured blow-up of a material which being heated in the thermoformer oven in a forming station or thermoformer, such as by a linear variable differential transformer, in order to adjust the thickness of the plastic material by regulating the temperature of the oven prior to the conveyance of the material into the molding or forming station.

Abstract: An extrusion die-set is disclosed for extruding plastic film, in which the nozzle-lips (6,8) are heated, for the purpose of allowing production speed to be raised without losing film-quality. The heaters include aluminum rings (62,82) embedded in grooves in the dies near the nozzle lips. The surfaces (66,67,86,87) of the ring that face away from the nozzle lips are cut away, so that heat transfer to the bulk of the dies (60,80) is reduced. The disclosed heaters eliminate the problem of hot-spots and cold-spots around the circumference of the nozzle. The nozzle lips can run several degrees hotter than the bulk of the dies, using the disclosed heaters.

Abstract: A Heater-Cooler unit that provides efficient heating and cooling in such a manner that the temperature is easily controlled. The unit's 360 degree exposure enables both fins and barrel surface to be in complete contact with cooling air. The structure of the fins provides contact with the barrel to conduct heat flowing from the heating elements to the barrel surface.

Abstract: An apparatus for molding and curing a resin matrix composite material under pressure and heat by a use of a bag provided in an autoclave for covering the material and applying the pressure to the material.

Abstract: A method for curing rubber in a heated mold in which the temperature of the mold is measured after closure and variations in temperature from an optimum cure temperature are used to adjust elapsed cure times which decrement an optimum cure time. The adjustment of elapsed cure time is determined by an algorithm which utilizes the 18.degree. F. (10.degree. C.) doubling rule; that is, that the rate of cure doubles for each increase in temperature of 18.degree. F. (10.degree. C.) and halves for each decrease in temperature of 18.degree. F. (10.degree. C.). Accordingly, the algorithm reduces the cure time remaining at a rate exceeding the actual elapsed time if the temperature of the mold is measured and determined to be above the optimum or set point temperature, and conversely, the cure time remaining is lengthened by reducing the cure time remaining at a rate below the actual elapsed time rate if the measured temperature of the mold is below the set point temperature.

Abstract: A method for controlling certain parameters of an injection molding cycle applying PVT optimization wherein the injection pressure and injection velocity of the melt are utilized to calculate an average viscosity for the melt during injection in a qualifying cycle of the machine as well as subsequent production cycles. A ratio of the average viscosity in a given cycle relative to the viscosity in either the qualifying cycle or a preceding cycle is utilized to adjust the holding time and cooling time, thereby achieving PVT optimization. In a second aspect, an injection molding machine is utilized to develop PVT constants for a given material by pressurizing the material in the barrel against the blocked outlet nozzle, measuring the volume during pressurization, and then weighing the pressurized shot after it is purged from the barrel in order to calculate the specific volume of the material.

Abstract: The heat-sink capacity of a thick-walled article being cured with a hot liquid supplying heat to one side of the wall, allows the point of least cure (PLC) to receive a higher rate of cure equivalents even after the hot liquid is replaced with a cold liquid. In the mean while, on the other side of the wall continues to be heated. Because such a change-over is effected before the PLC has received the minimum number of cure equivalents required to effect a cure at the PLC (a "pre-cure change-over"), a valving arrangement is provided which allows the changeover to be effected without permitting a pressure drop in the bladder sufficient to permit the tire to "blow" because it is as yet uncured when the change-over is effected. Such a pre-cure change-over cannot be made when steam is replaced with water at ambient temperature.

Abstract: A process for regulating the heating of a thermoplastic band used in a station for thermoforming upwardly open containers, the process being characterized in that, in a zone of the softened thermoplastic band, zone surrounded by a mesh of rigidified matter, the degree of deformation of this zone under the action of a predetermined mass is measured, the measured value of the degree of deformation is compared with a predetermined reference value corresponding to a good aptitude to thermoforming, and the heating of the band is regulated as a function of the value of deformation measured so that the deformation corresponds to the reference value.

Abstract: An analytical technique for controlling the curing process of fiber-reinforced composite materials that are formed using thermosetting resins. The technique is the percent gel method and involves development of a time-to-gel equation as a function of temperature. From this equation a rate-of-gel equation is then determined, and a percent gel is calculated which is the product of rate-of-gel times time. Percent gel accounting is used to control the proper pressure application point in an autoclave cure process to achieve desired properties in a production composite part.

Abstract: Method and apparatus are disclosed for inducing dimensional stability in cured composite structures using acoustic emission analysis to identify the appropriate level and extent of coincident thermal conditioning. Temperature of the composite structure is lowered at a bounded rate to a minimum temperature typical of the intended operating environment. Passive stress wave acoustic emissions of the composite are analyzed to generate a signature of stress relaxation events over time. When the rate of stress relaxation events decreases below a predetermined percentage of the maximum rate, and remains below that level for a period of time sufficient to predict operational stability, thermal conditioning is terminated.

Abstract: In a method of operating a screw extruder having a drive motor in which the speed of rotation of the drive motor is controlled, in order to achieve as constant a quality of product as possible, the speed of rotation is controlled depending on the specific energy input in such a manner that the specific energy input is maintained substantially constant. A control depending on the product temperature may advantageously be superimposed on the control keeping the specific energy constant in the form of a cascade control. A screw extruder for carrying out the method has a housing in which a screw is mounted, a drive motor having a variable speed for continuously driving the screw, feed devices for supplying basic products, additives and the like, and a control device for controlling the speed of rotation of the screw.

Abstract: A method of molding expandable thermoplastic polymer beads in a mold to form articles of foamed material comprising: pulsing steam through at least one of the cavities to contact and expand the beads in the cavity for a finite period of time and drawing the steam amongst the beads by providing reduced pressure to at least one of the cavities for the same period of time; and pulsing mist through the expanded beads by providing mist to at least one of the cavities and drawing the mist through the expanded beads by providing reduced pressure to at least one of the cavities for the finite period of time of predetermined duration to form articles of foamed material.

Abstract: A control process for foaming and fusing plastics in a foaming and fusing device, and a fusing device for carrying out the process, in which the control process works in cycles, each cycle consists of phases which are at least an injection phase, a heating phase, a fusion phase, a cooling phase and a mould release phase, such phases being started and completed depending on control criteria comprising a time period, a pressure or a temperature limit value for the conditions evolving in the device such control criteria belonging to a certain cycle comprising a control criteria set, and with each cycle quality values of predetermined characteristics determined by measurements taken from the respective plastic part or an agglomerate cake situated in the device, a new set of control criteria being generated for each new cycle from prior control criteria depending from the quality values measured with such prior cycle of the control process, wherein the quality values of each cycle are combined to a deviation which

Abstract: A method is suggested which is used for controlling and/or regulating of the injection molding in injection molding machines by measuring the temperature in the injection tool. A thermosensor is fed within a bore in the tool very closely to the molding pocket surface, so that the temperature fluctuations resulting from the injection cycles can be registered by the thermosensor. The measuring results are controlled with respect to maximum permissible deviations, whereby it is advantageous to control the minimum temperature and the temperature difference between the maximum and the minimum temperature. When exceeding predetermined maximum permissible deviations a signal is actuated for controlling a quality control for sorting out of parts and/or a light signal or an acoustic signal and/or the machine is switched off. Moreover, the measuring signals are used for controlling of the tool temperature and the mass temperature.

Abstract: A method of binder removal from a green body before sintering or the like wherein the binder is constituted of a polymeric material or mixture which is degradable by thermo-oxidation and the green body is initially heated to a temperature where the binder reaches an energy level above the activation energy of the binder, as a result of which exothermic degradation reactions are initiated at the binder-atmosphere interface. The rate of the exothermic reaction is controlled by the rate of supply of thermal energy and oxygen to the reaction site as well as the rate of evacuation of the heat of reaction generated during the thermal oxidation. Substantially all of the binder is thus removed from the green body which can then be sintered in accordance with the practices of the prior art.

Abstract: A screw extruder and a method of operation thereof. The screw extruder comprises a barrel including a section that is supported for rotation about the longitudinal axis of the barrel. A screw extends and is supported for rotation in the barrel; and, in use, rotation of the screw rotates and advances plastic material through the barrel. Rotation of the screw also causes the rotatable barrel section to rotate, and a brake is connected to that rotatable section to maintain the rotational speed of the rotatable section less than the rotational speed of the extruder screw. The rotational speed of the screw relative to the rotatable barrel section controls the relative rates at which plastic is mixed, heated, and pressurized in the barrel.

Abstract: The apparatus for extrusion of a thermoplastic material comprises an extruder with an extruder screw and an extruder housing with a feed opening, a feed device, a drive with a variable speed motor and a regulating device cascade for the mass temperature. The regulating device cascade has a plurality of tempering zones, at least one mass temperature detector and at least one tempering device. One tempering zone connected directly to the feed opening is part of the regulating device cascade and the temperature in the one tempering zone is corrected by a set value during a mass temperature variation. To provide a temperature regulation range which does not experience disturbing decreases, the tempering zone at the feed opening has only a cooling device and has a grooved sleeve. The feed device is a gravity feed device and belongs to an additional regulating loop which controls the rotational speed of a variable speed motor.

Abstract: An inner conical recess fitting (1) which is connectable to the prosthesis and is intended for receiving a stump (17) of an amputated extremity can be fitted directly to the stump (17) without the aid of modeling in the following procedural steps: to mold the inner conical recess, a plastic which is shrinkable through the action of external influences, such as heat, is selected; a tube (14) which is made of this plastic and is open at at least one end and has a smaller diameter and a smaller length than the inner conical recess fitting (1) to be manufactured is extended and stretched, so that it has in every direction a greater dimension than the inner conical recess fitting (1) to be manufactured; and the widened and stretched molded piece (10) is placed on the stump (17) and is made to shrink through, e.g., application of heat at selected locations, until the fitting bears everywhere securely against the stump.

Abstract: A method of forming a foamed plastic article, comprising the steps of: injecting pressurized gaseous bubbles into a stream of heated liquid plastic; feeding the heated liquid, with entrained gas bubbles, into a mold cavity without expanding the bubbles; slowly expanding the mold cavity to permit the gas bubbles to expand and thereby produce a foamed plastic article; controlling the temperature of the mold cavity surfaces so that the plastic material is in a viscous liquid state during at least the major part of the bubble expansion process; and cooling the mold cavity surfaces to a temperature less than the melt point of the plastic.

Abstract: A curing press for tires is operated with a minimum curing time which will provide the near-optimum number of cure equivalents at the point of least cure without locating it. An average temperature for a particular period during the year is "set" in a programmable controller ("PC") based on minimum and maximum temperature measurements made in the curing room during the day and night over a preselected period of time. The actual ambient temperature is measured at the press, which temperature is essentially that of the green tire just before it is loaded in the prss. The PC controls operation of the press, and is used to provide a near-optimum but variable curing period, depending upon the difference between the "set" temperature and the actual (green tire) temperature, and whether it is greater than, or less than the "set" temperature, to provide a near-perfect cure without tracking the point of least cure.

Abstract: Apparatus for coinjecting a plurality of thermoplastic materials to mold an article having a layered wall structure using thermoplastic material having different optimum processing temperatures including the maintenance of the optimum temperatures in flow paths individual to each material from its source to a mold cavity.

Abstract: A fast-cure process of manufacturing concrete products of critical shapes and strength requirements such as block, tile and pipe provides substantially maximum strength in a few hours as compared with the many months it would take in an ambient atmosphere. Critical shape is maintained without cracks, etc., by control of temperature, humidity and atmospheric CO.sub.2 within a kiln in which the uncured concrete products reside. The humidity is kept at saturation until substantially all the concrete reacts chemically with the water. The temperature is controlled to prevent excessive temperatures at critical times and to accelerate cure when the products can stand higher temperatures. Free hydrated lime is fast cured by a CO.sub.2 rich atmosphere at elevated temperature.

Abstract: In a method and apparatus for continuous shaping of carbon-fiber-reinforced plastic tubes, a carbon fiber prepreg in tape form impregnated with a first thermosetting resin is laminated on and around a mandrel; the laminate provided on said mandrel is preheated; and the preheated laminate is pulled in and through a hot die together with the mandrel, during which it is gelled, cured, and shaped into a carbon-fiber-reinforced plastic tube, wherein a second thermosetting resin is uniformly supplied onto the outer circumference of the laminate in a resin squeezing zone in the hot die.

Abstract: The invention relates to a method for producing insulations of foamed plastic material, in cabinets and doors of refrigerators, freezers and the like.According to the invention, a metered quantity of a foamable mixture is fed into the gaps between the inner and outer walls of a cabinet or door, placed in a foaming jig; the foaming process is controlled by sensing characteristic parameters, for example, the temperature of the jig, cabinet or door, or the pressure of the foaming plastic material, comparing them with reference parameters or data stored in a data processing unit. A control signal is generated to open the foaming jig and to unmold or remove the cabinet or door when at least one of the processing parameters has reached a pre-established value. The metered quantity of mixture fed in each subsequent foaming operation is corrected each time according to the changes in the peak pressure of the foam with respect to the previous foaming operation.

Abstract: A novel process for providing a thermoplastic polymer having unique thermal characteristics including the step of cooling the polymer during extended mastication until the melt index of the polymer is substantially increased.

Abstract: A thickness control system for controlling the thickness of an extrudate includes a nested temperature control loop for controlling the temperature of a heat responsive element based upon a predetermined temperature set point. The temperature set point for the temperature control loop is computed based upon the measured thickness of the extrudate.

Abstract: The heat exchanger comprises a plurality of semicylindrical segments, coupled so as to substantially define a circular sleeve encompassing the body to be thermally controlled, the segments being axially stacked and provided with radially extending fins including throughgoing holes, in the two opposite lateral faces of the segments there being provided recesses for housing an electric resistance, and an outer casing being moreover provided which defines, cooperating with the segments, an air conveying path which successively extends on the outer and inner surfaces of the segments.